Engine anti-stall device



Feb. 16, 1960 H. IA. CARLSON 2,925,256

ENGINE ANTIf-STALL DEVICE Filed Oct. 2l, 1957 INVENTOR.

/M HARQLD A. :AR| soN ATTORNEY United States Patent ft ENGINE ANrLsrALL nEvrcE Harold A. Carlson, Brentwood, Mo., assigner tor-ACF Industries, Incorporated, New York, N.Y.,r a" corporation of New Jersey Application october 21,1957, serial No. v691,345 11 Claims. (ci. :6r-41) This invention relates to internal combustion engines and more particularly to an anti-stall feature for internal combustion engines.

Internal combustion engines generally will not run properly below some deiinitevminimum speedfora parj ticular engine. When the speed of. the engine falls below this minimum, from whatever cause, the engine isV likely 2,925,256 Patented Feb. 16, 1915i) ICC Y pressure below a predetermined -For purposes of illustration,` the inventionmis Yshown as applied to a carburetor. Ing'thc two disclosedembodiments, a pressure sensingdiaphragm motor respondsto a drop in fuel pressure toadmit additional airto the intake manifold of aninternal combustion engine. In the trst'embodiment,

the threttlevalveis opened anadditional amount from its normal idle or closed position to admit more air and l vfuel around Vthe throttle valve. In. the. second embodil l0 ment,f'an auxiliary valve is opened to permit -.additional air tofllow through a by-passaround the'. throttle valve.

The' invention will now be .described indetail with particular reference to the aforementioned embodiments, but it is to be understood that the invention..isapplicableto internal combustion engines generally,-. irrespective. of the fuelingv system, and is .not tobe limited to engines equipped with carburetors, but is equally applicable to other forms of fueling systems; for example, fuel injection systems.

2 0 `Referring toEig. l, acarburetor 1 has a body 2 land to stop Vrunning or, in other words, to stall. lMany faotors can cause engine speed to-be reduced 'below/.the

permissible minimum, thereby causing stalling.;T Included among these-.factors are very rapid deceleration, a reduc-v tion in pressure differential between the'ambientpressure allange 3 for attachment to the induction manifold (not shown) of an internal combustion engine. The carburetor body is tted with acover 5. secured thereto bybolts 7.

l A portion of .therboltsmay pass through thefbody 2, flange 3, .and into thel intake manifold An induction andk the intake manifold pressure as may resultfrorn improper-mixtureratio, improper ignition adjustment, an

increase `in altitude,xor an unduly poor grade offuel, .to name but a few. It is common practice to provide `internal combustion engines with 'antistall devices which usually operate responsive to a reduction in intake manihigh because of the condition of the valves, piston rings,V

or other factors. Anti-stall mechanisms; responsive. to manifold pressure must be mechanically coordinated with .throttle position so that they are operative only when the throttle is substantially closed to prevent their operation at open throttle under extremely heavy load conditions resulting in a relatively high intake manifold pressure. It is therefore an object of this invention to provide an improved anti-stall mechanism for. internal combustion engines. Y

Another objectA of thisinvention is to provide Yinternal combustion engines with a more sensitive anti-stall feature.

Stillanother object of this invention is .toprovide an anti-stall feature which `is simple and precise in operation. Still another object of this invention is to ,provideln internal `combustion engine with-an anti-stall feature responsive to fuel pressure.

Additional .objects and advantages will be apparent ,fromthe followingdescription and drawings, in whichz.

Fig. l isa fragmentary partial sectional elevation view f o f an ,embodiment ofV the invention as applied-to a carburetor. Fig. 2 is a sectional elevation view of another embodilment of the invention applied to la'carburetor similar .to

that illustrated in Fig. 1. Y

Briefly, the invention relates to yan anti-stall feature for admitting additional air to thecombustion area of an internal combustion engine, to prevent stalling of the en, gine under idling conditions, responsive to a drop'm fuel sive chokecontrol 13'is connected to a source of Vengine conduit 9l passesthro'ugh thecover. 5, body 2, andilange 3, and' includes an air horn 11 formed integrally with the cover' 5. The air horn` contains the normal pivoted choke (notishown),v Aconventional temperature responheatfsuch; as an exhaust manifold for maintaining. the choke closed during the warm-up period. A iloat system yincludes an inlet 15, iilter V16, and needle valve assembly.

117,' all in the cover 5, and a floatf19A pivotally-mounted in a fuel chamber Ztlin the body 2. .The oat 19 vwill drop pressure therein substantiallyk atmospheric. A main or responsive to a drop in fuel level in the fuel chamber 20 to permit` the needle valve assembly 17 kto open and admit fuel through the inlet 15 to the fuel chamber. 20. TheV fuel chamberV is conventionally vented to .maintain the high speed oriiiceV 25 in the bottom of the fuel chamber 20 opens into amain fuel passageway 27 fitted at one end with a nozzle 29 which discharges into aventuricluster 31 in the induction passage 9. A passageway, 33 through 5 the body 2 connects the nozzle 29 and the fuel chamber 2t) Atoprevent percolation. A metering rod 3S .is fitted in the main orice 25 and is responsive to an increase in engine speed to permit more fuel to'enter the main fuel Ypassageway 27. An idle tube 37 has an open lower end 38 for picking up fuel from the passagel 27. After fuel is drawninto the tube 37 it passes through a conventional idlesy'stem which may include a by-pass, economizer, and bleed,'.and.through a' passageway system 40 to the idle ports 43 and 44. The lower idle port 44 is provided with an idle adjustment screw45. A throttle valve 50 is fixed to a shaft y51 pivotally mounted in the llange portion of the induction conduit 9 and Vmay be manually actuated in any eonventional manner.v

`Referring now to Fig. l, the dashedA lines illustrate. the

throttle valve50 in its normally closed or idle position,

and .corresponds to the position of the throttle valve 50 in Fig. 2. However, in Fig. l sufficient-air` must pass the closed' throttle valve. to forma combustible mixture, whilein Fig. 2 the throttlevalvemay be tightly closed.

Fixed on the throttle shaft S1 is a fixed lever 55 having sensing diaphragm motor 72. Thediaphragm motor in- .a shoulder 5.6. Rotatably mounted on the throttle'shaft is a. rotatable 1ever58 having a dog 59 for engaging the shoulder 56 on the fixed lever' 55.v A fingervl 'on the rotatable lever v58 isfreely received in a hole '63 in a rodend member 64 on a -rod 65 journaled in an adjusting mit 67 threaded into an inner housing 71 of a'pressur'e cludes an outer housing 73 with a diaphragm 74 clamped therebetween as by bolts 75. The diaphragm 74 is provided with conventional rigid washers476 on either face thereof, andis secured to the rod 65 in any conventional manner as by 'a peened-over portion 79 of the rod, The inner housing 71 of 'the motor is provided with a cylindrical stop 80 to limit inward movement of the diaphragm 74. The 'outer housing 73 is similarly-provided with steps 81 to limit outward movement of the diaphragm.V AThe diaphragm 74 and inner housing 71 `define an atmospheric chamber 84 having an atmospheric vent 85. The outer housing 73 and the diaphragm 74 define therebetween a pressure chamber 87 having an opening 88 into a doubleended coupling portion 89. A spring '91 is received on the rod 6'5 and engages a shoulder 92 on the rod and the adiusting nut 67. The pressure sensing diaphragm motor 72 is rigidly mounted on the flange 3 bv a bracket k94 secured to the flange by bolts 95. A nut 96 threaded on the casing 'rigidly secures the motor to the bracket. l The fuel system includes a tank v97, a fuel pump 98, the pressure sensing diaphragm motor l72. and the fuel inlet 15 in the carburetor cover 5, connected in series by conduits. The only requirement of the pump 98 is that the delivered fuel pressure from vthe pump in the idle speed range be proportionate lto the engine speed. Suitable pumps-of this tvpe are shown in United States Patents Numbers 2,786,423 and 2.803,265, and usually deliver 2 5 p.s.i. fuel pressure at idle speed.

The operation of the embodiment illustrated in Fig. l 1s as follows: With the engine operating at idle speed, the position of the throttle valve 50 will vbe as shown by the dashed lines and 'the throttle will Vbe in the normal closed position. Fuel is drawn from the tank 97 through the pump 98 'and then through the connection 39 on the pressure sensing diaphragm motor 72 and into the fuel inlet 15 of the carburetor 1. Normal pressure of the fuel in thepressure chamber 87 of the pressure sensing motor forces the diaphragm 74 to the position shovim. The linkage between the diaphragm 74 and the rotating lever 58 on the throttle shaft 51 is such that the dog 59 engages or nearly engages the shoulder l56 of the fixed lever 55 on the throttle shaft. Should the engine begin to stall, that is, should the engine speed fall sufliciently below the normal idle speed that the engine would be likelv to die. the speed of the fuel pump 98 will likewise fall, resulting in a reduction in vfuel pressure between the pump and the fuel inlet 15 in the carburetor. This reduction in pressure is, of course. reiiected in the pressure chamber '87 of the pressure sensing diaphragm motor 72 and the spring 91 urges the diaphragm 74 outwardly to the position shown by the phantom lines 74'. This motion of the diaphragm is transmitted `through the rod 65 and the rod end coupling 64 and finger 61 to rotate the rotating lever 58 counterclockwise to the position shown by the phantom lines '58. The Ifixed lever 55 on the throttle shaft is rotated lby the dog 59 to the position shown by the phantom lines 55 thereby rotating the throttle valve to the position shown Vby the phantom 'lines 50. With the throttle cracked open in this manner, additional air is permitted to enter the engine, increasing its speed, as is well understoodin the art to which this invention pertains. As the engine speed increases, the pump speed simultaneously increases resulting in a higher pressure in the pressure chamber 87 of the pressure sensing diaphragm motor again .restoring the throttle to its normal idle position 50.

Referring now to the embodiment illustrated in Fig. v2, similar reference numerals indicate the same parts as in Fig. .1. The throttle valve .50 'is in the idle or closed position. As illustrated, the :throttle valve is tightly closed and any air passing Iinto the engine intake manifold passes through the port .102 .in the induction conduit 9, Vthrough the passageway 103 and into the manifold 4through a `slot '104 in `the-bottom ofthe flange 3. An adjustingscrew 106 is provided to permit adjustment of the quantity of air passing through port 102'. A passageway 103 extends upwardly into a chamber 109 which is connected with the induction conduit 9 by -a passageway 110. The juncture of the passageway 110 and the Vchamber 109 provides a seat 111 for a needle valve 112.. The needle valve is tapered at one end 113 to `engage the valve seat with a sealing't. The other end of the valve 'is fixed to a iexible diaphragm '115 having reinforcing washers 116 on either side thereof. A compression spring 117 engages one of the Washers 116 urging the diaphragm 115 outwardly. rthe diaphragm is clamped between a shoulder 120 on the carburetor body 2 and a clamping member 121 secured to the carburetor body in any conventional manner as by bolts. The clamping member 12,1 has a threaded passageway 122 communicating with the diaphragm 115 and defining a pressure chamber 123 for receiving a conduit 124 from the delivery side of the fuel pump 98.

The operation of the embodiment illustrated in Fig. 2 is as follows: When the engine is vat normal idle speed the fuel pressure delivered into the pressure chamber 123 forces the V needle valve 112 inwardly against the valve seat 111, preventing the entrance of air through the passageway 110. When the engine begins to stall,gthe pressure in the pressure chamber 123 will fall permitting the spring 117'to force the needle valve 112 outwardly admitting air through the passageway 110. The `air flows through the chamber 109, the passageway 10S, and past the port 102 adding to the air admitted therethrough, and then through the passageway 103 andthe slot 104 finto the engine intake manifold, thereby increasing Vthe speed of the engine and the fuel pump 98, which increases the fuel pressure in the pressure chamber 12,3 closing the valve 112.

Although this invention has been described with particular reference-'to certain embodiments, features, struc-v tural details, and functions in keeping witht'he -recited objects of the invention, various modifications and improvements will be apparent to one skilled -in the art, and the invention is therefore not to be limited to such embodiments, features, structural details or functions except as set forth in the appended-claims.

I claim:

1. In an internal combustion engine, the combination of, means for supplying air to said engine, means Yfor supplying fuel to said engine above a minimum pressure when said engine is operating at normal idle speed, means for mixing said fuel and said air to form a combustible mixture, and means to provide additional air for Vsaid combustible mixture responsive to a ldrop fin fuel pressure below said minimum pressure due to a -decrease in engine idling speed.

2. In a carburetor, means for receiving fuel `above fa minimum pressure, an induction conduit having a mixture portion Aand a portion 4for admitting air `to said mixture portion, and means responsive to a drop'in lfuel pressure to admit additional air to said mixture portion of said induction conduit when said 4carburetor iis in `the idle range.

3. In a carburetion system, means for supplying fuel above a minimum pressure to a carburetor, an induction conduit having a mixture portion and a Vportion for admitting air to said mixture portion wherein said Afuel and said air are mixed, said mixture portion being `defined by the portion of said induction conduitldownstream from a substantially closed throttle valve in ysaid induction conduit, and means for admitting additional air ,downstream from said throttle valve responsive to areduction in fuel pressure below .said minimum-pressure.

-4. In a carburetion system for an engine, means forsupplying fuel above a minimum pressure to a carburetor, van induction conduit ,having a mixture portion and a portion Afor admitting air .to said .mixture portion, .said mixture lportion being defined yby the .portion ofsa'idfinduction conduit 4downstream from a substantially l'closed throttle valve in said induction conduit, and means to open said throttle valve responsive to a drop in fuel pressure below said minimum pressure to admit additional air to the mixture portion of said induction conduit to prevent stalling of said engine upon a drop in fuel pressure.

5. In a carburetion system for an engine, means for supplying fuel to a carburetor at pressures varying as the speed of the engine during operation of the kengine in the general vicinity of the idle speed, an induction conduit in said carburetor, a throttle valve in said induction conduit, means for discharging fuel into said induction conduit downstream from said throttle Yvalve when said throttle valve is substantially closed and said engine is v operating in the general vicinity of said idle speed, a pressure sensing diaphragm motor including a'pressure chamber for actuating a diaphragm responsive to changes in the pressure of fuel delivered to said carburetor, and means interconnecting said diaphragm and said throttle valve to open said throttle valve when said engine is oper-l Y ating in the general vicinity of said idle speed and the pressure of said fuel drops below the pressure normally supplied when said engine is operating at said idle speed.

6. In a carburetion system'for, an engine, means for supplying fuel above a minimum pressure to a carburetor,y an induction conduit having a mixture portion and a portion for admitting air to said mixture portion, said mixture portion being defined by the portion of said induction'conduit downstream from Aa substantially closed throttle valve in said induction conduit, ahy-pass having one end opening into a supply ofair and the other end opening into said induction conduit downstream from said throttle for conveying air to said mixture portion, and means responsive to a reduction in said minimum fuel'pressure to open a normally closed valve in said bypass to permit additional air to flow through said bypass and into the mixture portion of said rinduction conduit. Q

7. In a carburetion system for an engine, means for supplying fuel to a carburetor at pressures varying as the speedof the engine during operation of the engine in the general vicinity of the idle speed, an induction conduit in said carburetor, a throttle valve in said induction conduit defining a mixture'portion in said induction con pressure chamber for actuating a diaphragm responsive to changes in the pressureV of fuel delivered to said carburetor, and means interconnecting said diaphragm and said valve to open said air valve whenY said engine is operating in the general vicinity of said idle speed and the pressure of said fuel drops below the normal pressure when said engine is operating at said idle speed.

8. In the carburetion system of claim 6, the first said endV of said by-pass opening into said induction conduit upstream from said throttle valve.

9. In an internal combustion engine, the combination of, means for supplying air to theA engine, .pump meansv for supplyingfuel to the engine, means to vary the output of said pump means with changes in engine Y speed withina certain range of engine speedsmeans`l` for mixing the air and fuel supplied by said first means and said pump, respectively, to form a combustible mixture for said engine, mixture control means `operative within said certain range of engine-speeds, and means connected to'saidpump means and said'mixture control means ,fork adjusting the mixture in accordance with changes in pump output. l

10. In an internal combustion engine, the combination of, means for supplying a fuel-air mixture forY proper operation of the engine within a certain range of engine speeds, means for controlling the speed within said speed range, a source of fuel for saidA first means, a pump connected with said source 'and supplying fuel under pres- Y 'Y Vsure to said first; means, means to operate saidr pump at speeds variable with engine speed s`o that pump output.` l changes Within the certain range of engine speeds, and

means connected withv said pumpy and responsive to changes in pump output Vconnected withl and operating said means for controlling .the engine speed.

11. In an rinternal 'combustion engine, the combination of, means for supplying a fuel-air mixtureforl operation of the engine within .a certain range Vof engine .Y I

speeds, means for controlling the fuel ratio delivered by said means, Va source of fuel for supplying said. first means, a pump connected with saidsource of fuel and delivering thel fuel from said source underpressure, to

said first means, means to'operate said pump at speeds variable withv engine speed so that pump output changes within the certain range of engine speed, and means con.- nected with said pump and responsive to changes in pump output connected with and'operating said `means for controlling the fuel ratio.

Mauory May 1, 1934l 

